1. Field of the Invention
The present invention relates to a reference current generating circuit, and a reference voltage generating circuit and a temperature detection circuit using the reference current generating circuit. In particular, the present invention relates to a reference current generating circuit including a MOS transistor, and a reference voltage generating circuit and a temperature detection circuit using the reference current generating circuit.
2. Description of the Related Art
A variety of semiconductor devices requires a reference voltage for operating. As a circuit generating such a reference voltage, a band gap reference circuit is known. A band gap reference circuit can supply a voltage higher than or equal to the band gap of silicon (about 1.25 V) without depending on temperature. Note that the band gap reference circuit was incapable of supplying a voltage lower than the band gap as a reference voltage.
In contrast, a reference voltage generating circuit that can generate a reference voltage lower than the band gap with a low power supply voltage which is lower than the band gap is disclosed in Patent Document 1. The reference voltage generating circuit disclosed in Patent Document 1 generates a reference current with small dependence on temperature and generates a reference voltage by converting the reference current into a voltage in a current-voltage converter circuit constructed by using resistors alone.